Offset Right-Turn Lanes on State Highway Systems

Many state transportation agencies including the Nebraska Department of Roads (NDOR) provide right-turn lanes (i.e., traditional right-turn lanes) or offset right-turn lanes (ORTL) at two-way stop-controlled intersections for smoother traffic flow and improved safety. In some instances existing roadway shoulders are improvised into right-turn lanes by re-striping the pavement. The safety and economic benefits of these improvements are not well-known. In many reconstruction projects NDOR staff is faced with the question of whether a traditional right-turn lane or ORTL should be provided at a two-way stop-controlled intersection. The situation is further complicated at locations where existing roadway shoulders have been re-striped into right-turn lanes – should this improvised right-turn lane be removed to restore the highway to its original design, replaced with a traditional right-turn lane, or reconstructed with an ORTL? NDOR’s guidance is that new right-turn lanes in high speed rural areas should be ORTL. This guidance is a “should” condition with approval not to offset the lane only recommended by the Traffic Engineer and approval from the Roadway Design Engineer. Existing right-turn lanes are also reviewed on a case by case basis to determine if they should be offset, remain in place as is, removed, or modified with a project. Items reviewed in the decision making consist of existing and project traffic volumes, past crash history and Highway Safety Manual (HSM) prediction methods, and past communication or history of the location. There is a need to research the issue of right-turn lanes on high speed Nebraska state highways to provide comprehensive guidance on dealing with the issue. Since the issue is more critical on two-lane highways therefore, they will have priority over expressways in this research.